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TPU 60A Soft Robotics: Stronger, Flexible 3D Printing with Filaflex

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3D-Printed TPU 60A: The Future of Soft Robotics Without Silicone or Molds

Forget messy silicone casting and rigid TPU. This groundbreaking study from Kyoto University of Advanced Science proves that highly flexible TPU 60A and 70A can be 3D printed with outstanding results—producing grippers that are stronger, more flexible, and faster to fabricate than traditional soft robotic designs.

The Problem: Silicone Molding and Rigid TPU Are Holding Us Back

For years, soft robotic grippers have relied on silicone molding—an outdated, time-consuming, and fragile method that involves complex mold-making and long curing times. While FDM 3D printing has emerged as an alternative, most implementations have used TPU 85A, which is often too stiff for high-performance soft robots.

The Breakthrough: TPU 60A and 70A as Viable FDM Materials

This study shows that soft TPU materials like Filaflex 60A and 70A can be successfully 3D printed on a standard Prusa MK4 printer to create complex geometries such as pneumatic bellows. The results far surpass silicone-based methods in both flexibility and durability.

Each gripper took around 10 hours to print—no molds or curing needed.

Side and isometric view of the 3D-printed bellows-style soft finger
3D-printed bellows-style soft finger geometry—achieved without silicone molds.

Powerful Performance: Force, Flexibility, Versatility

  • Raw Force: The 60A TPU gripper lifted 1297 g (a full spool of filament) vs. only 230 g for a silicone-based version.
  • Flexibility: At 200 kPa, the TPU 60A gripper bent to 104°, the 70A to 81°, while 85A barely reached 42°.
  • Versatile Grip: Thanks to its pneumatic triangular design, the same gripper handled delicate items (like a 55 g egg) and heavy tools.
Demonstrating maximum lifting capacity: TPU 60A gripper lifts a 1297 g filament spool.
Bending angle comparison: TPU 60A, 70A, and 85A
Bending angle comparison: TPU 60A shows more than 2x the flexibility of TPU 85A.

The Technical Recipe: Yeoh 3rd-Order Hyperelastic Model

To give engineers a simulation-ready toolkit, the team validated the Yeoh 3rd-order hyperelastic model as the most accurate way to simulate TPU 60A/70A in FEA software. With just 6° of error margin, this model enables reliable digital prototyping—saving time and materials.

Yeoh model parameters table for TPU 60A and 70A
Accurate Yeoh 3rd-order hyperelastic model parameters for TPU 60A and 70A.
Simulation vs. experimental bending validation for TPU 60A
FEA simulation closely matched experimental TPU 60A behavior—with only 6° deviation.

Conclusion: A New Era for Soft Robotics, Powered by Filaflex

This research proves that materials like Filaflex 60A and 70A are not just printable—they outperform traditional silicone in almost every way. Stronger grip, higher bending angles, and faster, mold-free production make them ideal for the next generation of soft robotic systems.

The future of flexible, functional robotics is not molded—it's 3D printed.

Source

“Materials and Methods for Designing 3D-Printed Soft Robot Grippers in Low-Hardness TPU (60A–70A)”
Khalid Meitani, Sajid Nisar. IEEE Access, Vol. 13, 2025.
DOI: 10.1109/ACCESS.2025.3642169

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